Electronic procurement $($e$-$procurement$)$ is:

a$.$

The electronic integration and management of all procurement activities, including purchase request, authorisation, ordering, delivery and payment, between a purchaser and a supplier.

b$.$

none of the above

c$.$

An indication of efficiency of inventory turn calculated by the cost of goods sold divided by the average inventory.

d$.$

The coordination of all supply activities of an organisation from its suppliers and partners to its customers.